The description relates to a dispenser for liquids, or for viscous or sprayable products, to which is interchangeably tightly fitted a storage container and which is connectable to a dosing device, with a suction or pressure piston movable backwards and forwards in a cylinder housing and a valve between the suction and pressure sides.
Such dispensers are in every day use, e.g. as soap dispensers, lotion or cream dispensers, gels, liquid detergents, but also in the pharmaceutical sector as atomizers for medicaments. Whereas in the case of every day liquids such great importance is not attached to the special features of the chemical behaviour, this question is of considerable importance with medicaments. The components used in medicament spray containers are pump systems with in each case a unit formed from a connecting piece, sealing housing, piston with a compression spring and with a ball. As the balls and compression springs for functional reasons are made from steel or stainless steel, within a short time between the medicament liquid and the material steel chemical reactions can occur, which modify the fundamental substance of the medicament, so that such a pump system is not allowed for medicaments.
Medicamentous treatment by spraying ultra-fine droplets into the nose has increased greatly over the last few years. Three fundamental demands are made on such systems, namely reliability, safety and effectiveness. However, these conditions are not fulfilled with nose drops either for children or adults. One of the prerequisites is that the liquid is sealed by a valve from the environment in order to prevent the access of oxygen, bacilli and bacteria. Thus, known systems comprise a connection to a spraying device, a sealed housing, a piston, a measuring chamber, a spring located therein, the cylinder for the piston and a ball as a valve. The medicament comes into contact with the steel ball and compression spring, which represents a disadvantage of such systems.
The problem of the invention is to provide a dispenser suitable for liquids of different consistency preventing contact of the liquid with the metal parts and access for atmospheric bacteria.
According to the invention this problem is solved in that the cylinder housing receives at one end the piston with a compression spring located in a cavity and where at the other end is provided a valve seat with a circumferentially fixed membrane disk for blocking in the storage container or opening the flow out of the storage container. The compression spring located in the interior is the only part made from steel and does not come into contact with the liquid, so that even medicaments intended for spraying can be sprayed without any risk of chemical changes. The membrane valve prevents access for bacteria contained in the air, so that also here the liquid is protected against contamination.
A protecting chamber system has further features according to which the membrane disk has a central connecting opening to the cylinder housing and that in the valve seat are provided passage openings in the storage container.
The opening and closing of the valve is brought about in that the membrane disk is clamped to an outer edge between the valve seat and the cylinder housing and passage channels are provided in the cylinder housing, that the membrane disk engages in pressure-dependent manner against a concentric, outer ring land of the cylinder housing and that the membrane disk rests in spaced, pressure-dependent manner on an annular sealing seat around the central connecting opening. On sucking the liquid out of the storage container the sealing seat is opened and during the piston pressure stroke the sealing seat is closed in the direction of the storage container and freed to the dosing device.
Opening in the direction of the dosing device can advantageously take place in that the membrane disk is connected to the cylinder area and an upper area via the membrane disk to a suction or squeezing out opening for the dosing device.
An adequately large flow both in the suction direction and in the pressing direction is obtained in that the membrane disk with its connecting opening faces a suction or squeezing out opening of the cylinder housing. The connection between the valve seat and the cylinder housing is created in that on the side towards the storage container the valve seat forms a sealing locking connection.
According to further features the storage container comprises a transparent glass cylinder. Through the material glass, the container exerts no influence on the composition of the liquid.
From the constructional and manufacturing standpoint it is advantageous for an axially open glass cylinder to have a sealing clamping base made from a flexible material.
According to a further development of the invention, the liquid quantity is kept small without air bubble formation in that in the storage container is provided a flying piston adjustable by suction force.
The flying piston has a planar end face. The piston can be made from rubber or a plastics material able to slide easily on glass.
The surrounding of the steel compression spring can, according to other features of the invention, take place in that the cylinder housing has a hollow guide shaft for inner guidance of the sprung suction/compression piston.
According to further features the separate housing of the compression spring is made possible in that the compression spring is placed in a cavity of the sleeve-like suction/pressure piston.
The pressing of air to be vented out of the area receiving the compression spring can take place in that in the outer sleeve wall of the suction/pressure piston are provided axially directed vent ducts.
A further development provides for the valve seat passing concentrically to the locking connection into a mounting support for a suction tube. Such a suction tube can be used in place of the flying piston.
An alternative dispenser construction is obtained in that the cylinder housing is made angular and from the upper area the suction or squeezing out opening is led on as an angular channel or duct. The angle can both be a right angle and an acute angle. This leads to favourable ergonomic manipulations for gripping, holding and operating the dispenser.
To bring about a maximum space utilization for a large liquid volume, it is proposed that the valve seat directed towards the storage container is hollow and forms together with the locking connection a ring step, which is movable into a correspondingly shaped annular space of the flying piston.
When the cylinder housing is arranged angularly to the storage container axis, by means of a connection channel is connected an inner tube, which is equiaxial to the storage container axis.
Before using the dispenser the latter is advantageously sealed from the external air. For this purpose the inner tube which is connected to the dosing device is surrounded by a protective tube.
In use or operating intervals of the dispenser it is also advantageous that the inner tube with the dosing device and the protective tube are provided with a removable protective cap.
According to another alternative, which operates with the flying piston, it is proposed that under the valve seat is fixed a needle holding bush in the cylinder housing and that in said needle holding bush is fixed a hollow piercing needle, whose channel is connected to the passage openings. The invention is further developed in that in the storage container a second piston is provided below the needle holding bush, a flush-mounted inner contour corresponding to the outer contour of the needle holding bush, the locking connection and the ring step of the valve seat.
The liquid used as the liquid mass to be filled or the viscous liquid or the liquid to be atomized can be filled between the flying piston and the second piston during the manufacture and assembly of the dispenser.